During the performance of a musical composition a special human environment comes into being. We aim to interpret the compositions as a specific class of human environment in order to utilise that for description of structure and dynamics of general human environment. In particular, we analysed four Bach-s fugas considering their motifs and introducing the concept of the energy of a motif. We used bosonic excitations from theoretical physics as an analogical starting point for this concept, with the aim of proposing a new way to shed light onto more complex human environments. The aim is neither to reduce music to physical theories nor to define new theories of music, but to approach the investigation of complex environments in a new way, using already existing concepts.